Management of HIV infection after triple class failure

Abstract

Resistance of Human Immunodeficiency Virus (HIV) to antiretrovirals is a clinically important issue despite the availability of five antiretroviral drug classes. Although the incidence of HIV resistance might have stabilized or even decreased in patients starting their first Highly Active Antiretroviral Therapy (HAART) regimen in recent years, the prevalence of failure to the three original antiretroviral classes is estimated to range from 2.1% to 16% after HAART initiation. International guidelines recommend the use of at least two active drugs in constructing a new antiretroviral regimen to obtain virologic success, and adding a compound with a different mechanism of action often increases the chances of virologic response. With the introduction of new drug classes and new-generation compounds of older classes in the antiretroviral armamentarium, the chances of achieving virologic success in patients with resistance to all three original antiretroviral classes are certainly higher than in the past. Patients who experience virologic failure and show resistance to new antiretrovirals are, however, described both in randomized trials and clinical settings. Although HAART regimens using various associations of the newest antiretrovirals led to very high rates of virologic success in patients with previous failure to all three original drug classes, there are circumstances in which patients cannot benefit from two fully active drugs, especially after prior exposure to several suboptimal therapies or functional monotherapies. These patients often need a holding regimen while awaiting new and effective antiretrovirals. This article reviews strategies that might be effective options to obtain virologic success in patients with triple class failure, and treatment strategies for patients who do not have two active drugs to construct a new effective antiretroviral regimen after virologic failure.